The invention relates to a method of a continuous determination of an instantaneous position of an impeller blade tip in a rotor turbine machine, particularly in a turbine impeller in a turbojet engine during its operation in a real condition in order to obtain a current information on a technical state of a blade.
During manufacturing, operation and repairing of a turbojet engine, before a destruction of turbojet rotor blades during their operation, an inspection and detection of blade states is needed for finding signals of an engine failure. It is particularly important in a real operational state and in a connection with a risk associated with it, e.g. during a flight.
U.S. Pat. No. 5,043,703 describes a method for monitoring of a microwave homodyne system for detection of any movement. The invention relates to making use of microwave homodyne system for an observation of a movement of an object in an observation field under microwave radiation.
In the known invention, the determination of a position of an object in static states is impossible because the observation is associated only with the change of a radio-wave frequency which is produced by a movement of objects in an observation field and which is not useful during a turbojet engine operation when the temperature is above 150xc2x0 C.
The object of the present invention is to arrange in a stable manner, in a selected place of housing of a rotor turbo machine and in a movement plane of an impeller blade tips, at least one microwave antenna with an aperture shape which is consistent with an internal surface of an housing, while maintaining conditions for a working medium in a form of an undisturbed gas flow. A microwave signal, which is produced by a microwave homodyne system, is emitted, and then received, through a microwave antenna. An output signal from that system, which carries out information on each instantaneous position of an impeller blade tip in relation to the antenna aperture, is converted by an electronic system, preferably by an electronic computer, and is read to isolate information on instantaneous, in a real time, position of blades both in relation to each other and in a plane of their movement.
A method according to the present invention allows to obtain a signal, which previously was very difficult to obtain, carrying information on an instantaneous, in a real time, position of impeller blade tips in a rotational turbine machine and signals carrying information on another mechanical effects occurring during an operation of that machine.